Return file snapshot on upload (#88)

#### What's this PR do?

The promise from 'uploadFile' now returns an object of the file data is decorated with a `pushKey` property that is the key generated by the call to `firebase.push`.  This change will give the caller the ability to access the urls, name and key for additional processing.

#### What are the important parts of the code?
a single `.then` with a spread

#### How should this be tested by the reviewer?
Ensure the caller of this function has access to the fileData in the returned promise.

#### Is any other information necessary to understand this?
This change is proposed as the caller may need to dispatch additional actions for use with redux/redux-observable that contain the information contained in the fileData.

src/actions/storage.js

@@ -81,6 +81,7 @@ export const uploadFile = (dispatch, firebase, { path, file, dbPath }) =>
       return firebase.database()
         .ref(dbPath)
         .push(fileData)
+        .then(snapshot => ({ snapshot, key: snapshot.key, File: fileData }))
     })
 
 /**